> In 1900 this dataset of 282 named timezones indicated 220 different offsets (from UTC), and while some of these were integers, (e.g. Europe/Prague, Europe/Rome), the majority were not - for example Moscow was 2 hours, 30 minutes and 17 seconds ahead.

Moscow changed after that to 2 hours, 31 minutes and 19 seconds for a few years before aligning with a ‘whole hour’ timezone. Fascinating - thanks for sharing!

Needs a 2021 in the title. I was curious if it took into account the controversial changes in the tzdb from 2021 https://www.theregister.com/2021/09/28/time_zone_database_co... since those would have changed the pre-1970 data.

But the visualisation was made around Jul 2021, so it avoids those changes (but also the more recent ones): https://github.com/colineberhardt/timezone-viz